idle surging up and down

[natedog910]

Just start car back up after doing a head gasket job
I checked 4 vacuum leaks none
If I shut car off and disconnect maf it idle fine why with it plugged back in there goes the surging up and down


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[aheroicrevolt]

I had the same thing. Recalibrate the Throttle position sensor per the TSRM sticky link here in the technical board. If it still surges swap the AFM for a known working one and see if its gone. Also, the wiring harness wires to the AFM plug are very brittle because off the heat on that side of the engine. After disconnecting my afm and plugging it back in it was doing the same thing. My problem was a wire had come loose inside the harness connector and once I pulled very gently on the wires the yellow one pulled right out of the connector. I crimped and solderd a new pin on the wire, pressed it back into connector and wahlah, surging gone.

So
1. TPS Calibration
2. AFM harness connector wiring
3. AFM sensor itself.

 

[natedog910]

I had the same thing. Recalibrate the Throttle position sensor per the TSRM sticky link here in the technical board. If it still surges swap the AFM for a known working one and see if its gone. Also, the wiring harness wires to the AFM plug are very brittle because off the heat on that side of the engine. After disconnecting my afm and plugging it back in it was doing the same thing. My problem was a wire had come loose inside the harness connector and once I pulled very gently on the wires the yellow one pulled right out of the connector. I crimped and solderd a new pin on the wire, pressed it back into connector and wahlah, surging gone.

So
1. TPS Calibration
2. AFM harness connector wiring
3. AFM sensor itself.

Will try

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[natedog910]

OK thanks 4 da help it was the iac valve got stuck wide open and I know why ,cuz I tried to start engine without throttle body piping connected so it must have went wide open and got stuck due to carbon buildup .so I removed iac and cleaned it car runs great now

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